Telephonic telegraphy



Feb. 13, 1934. v. BUSH TELEPHONIC TELEGRAPHY Filed Jan. 1o. 1930 mmm . .mwnhm Qmwlvf Q Q Y Patented Feb. 13, 1934 UNITED i STATES PATENT ori-ICE Various systems of high speed telegraphy are known in the art, which are, however, rather complicated and costly in operation. It is, therefore, the main object of the present invention to provide a system of telegraphy which accomplishes the results of high speed systems of telegraphy, which is more rapid and accurate and less expensive than present systems, and whichl pulses, without the necessity of adapting such a transmission system for this purpose. With these and other objects, which will become apparent in the course of the following description, the invention provides a system of telegraphy whereby code signals are produced and transformed into sound, the sound is transmitted over"` an ordinary telephone link, the received sound is again converted into electrical variations identical with the initial code signals and finally a telegraph printer or.` the like is operated by these received signals. It also contemplates the production of the initial signals as electrical variations at slow speed, their storage in a record, their conversion to sound and transmission as such at high speed, their reception in a similar record, and finally their reconversion to electrical variations andthe reproduction of the original message at slow speed. These and `other features of the invention will be more clearly understood by reference to the following detailed description, taken in connection with the accompanying drawing in which; 1

Fig. l is a schematic diagram of my system in its broader aspect, whereas;

Fig. 2 is a diagrammatic showing of aspecic embodiment of the invention, and

Fig. 3 is a diagrammatic section along line 3-3.

Slow speed connotes speedsused in the so'called start-stop telegraphs or in Morse apparatus. High speed" means a speed corresponding to a frequency of the magnitude of audible sequences of impulses, or generally, of a magnitude which can be recorded by means 80 used for the recording of sound impulses. Signal transmitter connotes apparatus for transmitting messages by means of electric impulses arranged according to certain codes, as for instance the so-called start-stop apparatus, Morse senders, and so forth. Signal receiver meansapparatus adapted to receive code messages as transmitted by signal transmitters, as defined above. Storing means includes any means adapted to accumulate electric signals in a form suitable for conversion into audible impulses and vice versa, as for instance'by the use of magnetic sound records, mechanical sound tracks or photographic sound tracks, which are suitable to be operated at varying speeds so as to-permit reproduction 'of the recorded impulses at speeds different from thev recording speed and vice versa. Impulse recorder refers to means adapted to receive signals in the form of electric impulses and to record these impulses upon storing means as dened above. Impulse reproducer comprises means for detecting recorded impulses from storing means as defined above and for converting them into signals in the form of electric impulses. Transmission means connotes any suitable means for transmitting sound, as for instance an ordinary telephone system or a radio telephone system, and so forth. An amplier is means, electrical, mechanical, or otherwise, which is adapted to increase the energy of impulses, preferably without having an inherent inertia, as for instance amplifiers employing electron discharge apparatus.

Referring now to Fig. .l ST is a signal transmitter, as for instance the sender of a printing telegraph of the start-stop type which produces 'electric impulses of a code system adapted to operate a corresponding receiver SR at the receiving station. The operation of keys or similar means of the signal transmitter sends a series of impulse Agroups of a code system which at the receiving station operate relays or similar means for selecting and printing characters corresponding to the impulse groups coming from the sending station. RCS is an impulse recorder adapted to record the impulses or impulse groups coming from ST, as indicated, upon storing means'W. The impulse recorder may, for instance, be a socalled Poulsen telegraphone which in its customary form consists of a telephone transmitter whose electrical vibrations magnetize transversely a moving steel wire, producing in magnetic record a replica of the speech. In reproduction this wire is caused to move in front of a soft iron armature of a coil of wire. The electrical variations thereby produced in the coil are conducted to a telephone receiver and there reproduce the original speech with remarkable faithfulness. As used in the system according to the present invention, the telephone transmitter of the telegraphone is replaced by the signal transmitter and the voltage supplied by the signal transmitter has to be adjusted to suit the telegraphone. However, any other impulse recording means, as for instance sound recorders producing sound tracks on discs, rolls or strips, or producing photographic sound records, may be utilized.

The storing means W upon which the impulses coming from RC are impressed is moved with a certain constant speed permitting a clear reception and'distinct separation of the signals. In order to conserve storing material, means can be provided which move the recording material only during the actual sending of signals. Any means making the feeding of the storing material dependent upon the operation of the signal transmitter are suitable for this purpose and a specific embodiment will be described later. As a result, the storing means will'now be impressed with the code signals of the message, without any unnecessary intervals between impulse groups.

RPS is an impulse reproducer adapted to deduct the signals recorded upon the storing means, as for instance a telegraphone receiver if steel wire is used for storing the signals magnetically, or a light sensitive apparatus if the signals are stored photographically. The storing means progress through the impulse reproducer at a speed which is higher than the speed at which the storing means moved through the impulse recorder, a feature which will be discussed more in detail later on. The speed at which the storing means is now moved will be selected so as to produce a sequence of impulses at an audible high speed frequency, so that these impulses can be used to operate a sound producer L, with the aid of lan amplifier A if necessary. The sound producer is juxtaposed to a sound transmitter, as indicated by an ordinary telephone transmitter T, which is connected through a transmission line TL to a telephone receiver R.

The kimpulses recorded upon the storingsneans W, when the latter is fed through RPS, thus produce sounds at L which are reproduced by R at another transmitter M, for instance the microphone of a telegraphone or impulse recorder RCR which is built like recorder RCS except that it has receiving means M (corresponding to ST connected with RCS) and that thestoring means W' progress therethrough at a speed corresponding to the speed used at RPS. Again, suitable amplifying means A may be interposed between M and RCR. After being impressed with the signals of audible frequency coming from M, the storing means W is fed with a speed which corresponds to that used in RCS, throughimpulse reproducer RPR, which substantially corresponds to reproducer RPS except in the speed of the storing means and the connection with SR instead of with L.` The speed of the storing means at RPR corresponding to that at RCS, the impulses recorded on W are delivered into the signal receiver SR as produced by ST, so that SR will print the messages as if directly connected to ST. An amplifier A may between RPR and SR.

It will be noted that the system according to my again be interposed invention transmits telegraph messages over a telegraph as used in the usual manner produces electric variations in the wire connecting the instruments with a maximum permissible frequency of not more Athan twenty cycles per second. Supposing that the keys are pressed at the rate of one hundred and eighty per minute, which is a. high speed of operation of the key board, a rate of three per second would result. The code signals consist on the average of about two cycles each. Thus six cycles per second will accomplish the transmission. To this must beV added a factor to insure clarity and twenty cycles per second will be a conservative figure for direct printing telegraph operation not utilizing multiplex transmission. Even a very poor telephone circuit is readily capable of transmitting one thousand cycles per second, which is fifty times the above figure. In the apparatus as described above, therefore, the storing means during transmission may move fty times as fast as they do in the recording on reproduction. An operator may, therefore, typewrite messages continuously for two hours. These may be transmitted during a three minute telephone call with time for arranging the apparatus, and the receiving printer will require two hours to print the received message, although the latter may be slightly accelerated. Of course, instead of one instrument working two hours at each end, there maybe several instruments at each end working a fraction of this time. It is evident that the speed here obtained is far above thatvattainable by present systems and that cost of operation per word transmitted may hence be very low. Also, it is to be noted that there is no manual operation beyond the operation of the key board so that the errors inherent in any system of telegraphy which involves telephoning or sending by messenger to a. central station are avoided. There are also avoided the delays inherent in present systems, for a message may be sent as fast as it can be typed and a telephone call put through.

A specific embodiment of the invention making use of a start-stop printing telegraph of the Kleinschmidt type, and of a Poulsen telegraphone will now be described in the form of a sending and receiving station, substantially arranged as explained above, butI with the amount f of apparatus necessary and with means for' properly operating each part of the apparatus according to its function within the scheme of the invention. It will be apparent that the elements used in the apparatus to be described are known in the art, that the invention consists in thepeculiar arrangement in which they are interrelated, and that any other elements suitable for the same purpose may be used without departing in any wise from the spirit of the invention as defined in the appended claims.

Referring now more particularly to Figs. 2 and 3, MO is a motor driving over a shaft 1 and gears 2, 3, 4 and 5 signal transmitter ST, a signal receiver SR, an impulse recorder RC and an impulse reproducer RP. The motor may be an electric motor supplied through leads 9 and 10 and will usually be provided with a speed regulating device which has the purpose of keeping the speed of the motor within the limits necessary for the successful operation of the particular system of printing telegraph apparatus used. As mentioned above, the signal transmitter ST is in this case the sender of the well-known Kleinschmidt printing telegraph and comprises the following parts necessary for an understanding of the present invention, while other elements have been omitted .as unessential for this purpose. A number of keys, one of them being key l1, are provided with extensions 12 actuating a U-shaped bar 13 common to all keys when any of the keys is depressed. The arm 14 of bar 13 is connected to a slide bar 15 which has an extension 19 and a cam 16 and is attached to a fixed support 20 by means of a spring 18 and a pin 17. Bar 15 cooperates with two bell-cranks 21 and 22 fastened upon 20. Gear 2 drives a shaft 24 and a coupling 25, 26, the sliding coupling half 26 being released and brought into contact with the constantly rotating half 25 by spring 29 every time one ofthe keys 11 is depressed, whereby the hook-shaped end 30 of sliding bar 15 operates bell cranks 21, A22 and brings extension 23 out of contact with cam 28. Soon afterwards 21, 22 are released by cam 16 depressing 15 when it slides backward'over pin 17, whereby 23 moves backward and disengages the coupling after one turn of shaft 24 by moving coupling half 26 to the left,- 23 sliding on the curved side of cam 28. During this turn the coupling half drives, through shaft 31, a cam mechanism which islnot shown as it isunessential for an understanding of the present invention. This cam mechanism operates consecutively, under the influence of the particular key depressed at that time, a certain number of contact pairs 32 which are connected in parallel by conducting bars 33, 34 but insulated from each other by insulating bar 35, and which are in series with a battery 36 and ground. In this .manner a certain selected group of impulses is produced, to be transmitted over lead 37. Provisions are made to keep bar 13 depressed and bar 15 in corresponding position during the sending of the impulses, that is during the turn of shaft 31, so that extension 19 closes a pair of contacts 40, 41, in series with lead 43, battery 42, and ground, during the sending of each impulse group corresponding to the depression of a key. The distances between 30 and 21 and 19 and 41 are so chosen that 40 will make contact with 41 a short time before the coupling is operated, and open the contacts again a short time after the coupling is released. If a printing telegraph is used which releases the keys immediately after they have been depressed, time relay can be inserted for bridging contacts 40 and 4l during the time necessary for sending the impulse group corresponding to the ,depressing of a key.

SR is a printing receiver adapted to cooperate with the sender ST. Here again only the parts ordinary telephone system.

may begin to turn and to operate the printing mechanism.

RC is an impulse recorder making use ofan impulse storing steel wire according to Poulsen. Its essential parts are a recording electro-magnet 61 in series with lead 63, battery 62 and ground, two rolls 64 and 65 for the wire W and a gear for moving the wire with one of two speeds, or for disengaging it altogether from the driving means. Any suitable gear may be used but the following construction will be described. Shaft 71 driven over gear 3 has a small gear wheel 73 and a large gear wheel 72 which drive gear wheels 74 and 75. A friction coupling with three discs 76, 77 and 78 is` provided, disc 78 being fixed to a shaft 80 which, with a square extension 81, slides in a corresponding recess of shaft 87 of roll 64 and can be shifted by means of lever 82., Disc '77 is connected with gear wheel75 by means of a hollow shaft 88 surrounding shaft 80. Gear wheel 74 is attached to shaft 79 with disc 76 by means of a friction hub 83 provided with an arm 84 cooperating with bell crank 85 which forms the armature of a solenoid 86 connected to lead 43 and ground. It willbe seen that by shifting lever 82 the wire'may be operated at two different speeds or not at all, and that roll 64 can be driven at low speed, over gear train 3, 73, 74, 83, 79, 76, 78, 81, 87 only when arm 84 is released, that is when solenoid 86 is energized. RP is an apparatus for converting the magnetic record of the Poulsen wire into electric impulses adapted. to operate receiver SR. It has the following essential parts. The wire W is. again supported by rolls 92 and 93. The record is detected by solenoid and if desired erased by erasing magnet 94 in series with battery 95 and switch 104. Roll 92 is driven over a gear which also permits two speeds, or disengagement of the wire transporting means. This gear consists of a shaft 102 115 means of al lever 101. Gear wheel 97 corresponds 120 to wheel 99 and wheel 96 to 98. They are mounted on shaft 103 driving roll 92, either over 4, 102, 99, 97 and 103 with low speed, or over 4, 102, 98, 96 and 103 with high speed.

A is an amplier of the well-known kind comprising electron discharge tube 111 with plate, grid, and a filament, grid, plate, and filament batteries, and transformers 112'and 113 which connect the amplifier to leads 114 and 91. L is a loud speaker with ground connection and vlead 18o 121, M'is a microphone with ground connection and lead 122. T, R and TL'are transmitter, receiver and transmission line respectively of an' 123 and 124 are change-over switches.

1 The operation of the apparatus as shown in Fig.

2 is as follows: At` the sending station, signal transmitter ST is operated as usual and the impulses sent over switch 123 to recorder RC, which is now driven at low speed over gears 73 and 74 as Idescribed above. Roll 64 will rotate only so long as 74 is released by means of solenoid 86 and switch 40, 41, that is, only during the sending of an impulse group corresponding to the depressing of one key. The wire is now transferred to RP which is run with high speed over 96 and 98, the magnetic record is detected at 90, erased at 94 if switch 104 is closed or preserved for another sending with switch 104 open, and the impulses transmitted over amplifier A and switch 124 to loud speaker L and the telephone system. At the receiving station the incoming sounds are received bymicrophone M and conducted to recorder RC over switch 123 which is now connecting leads 122 and 63. RC is run at high speed over 72 and 75 and the incoming impulses re corded on the wire. The wire is then transferred to RP, which is then operated at low speed, the magnetic records detected at and if desired erased at 94; and the low frequency impulses are conducted through amplier A, switch 124 and lead 55 to'signal receiver SR which will produce the printed message as if operated directly from ST. It Will be seen that the arrangement of Fig. 2 permits the storage of sending signals by ST and RC simultaneously with the sending of stored signals by RP and L, or the storing of received signals by M and RC simultaneously with the printing of stored impulses by RP and SR. The corresponding positions of the two change-over switches and the driving gears of RC and RP will be easily understood by referring to the above description of the apparatus in connection with Fig. 2.* This arrangement does not permit sending by operation of ST and RC simultaneously with the operation of M and RC, which however can easily be accomplished if desired by duplicating RC and RP, each of which would then only require al drive with onespeed, the arrangement being similar to that indicated in Fig. 1.

I claim: Y

1. The method of transmitting slow speed electric impulses which comprises the conversion of said electric impulses into high speed aerial sound waves of like characteristics, the transmission of said'converted impulses by suitable electric transmission means, and the reconversion of the latter impulses into electric impulses which are s'ubstantially like the original impulses.

2. The method of transmitting telegraphic messages which comprises the production of electric code impulses at a certain speed, the conversion of said impulses into aerial sound wavesignals at a higher speed, the sending of said signals over a system adapted electrically to transmit such signals, and the reconversion of said signals, at a lower speed, into electric code impulses substantially like the original code impulses.

3. The method of transmitting telegraphic messages which comprises the production of electric code impulses at low speed, the conversion of said impulses into aerial sound wave signals byrepeating them at substantially higher speed, sending said signals over a system adapted electrically to transmit such signals, and reconverting said signals into electric code impulses substantially like the original code impulses, by repeating them at a low speed.

4. The method of transmitting telegraphic messages which comprises producing electric code impulses corresponding to the signs to be transmitted, recording said impulses upon suitable storing means, reproducing said recorded impulses in form of sound waves in the air, transmitting said waves telephonically, recording the trans mitt'ed waves upon suitable storing means, and detecting and reproducing said recorded waves in a form substantially like the originally produced electric code impulses.

5. The method of transmitting telegraphic messages which comprises producing electric code impulses corresponding to the signs to be transmitted, recordingsaid impulses at low speed upon suitable storing means, reproducing said recorded impulses at high speed in form of sound waves in the air, transmitting said waves telephonically, recording the waves at -high speed upon suitable storing means and detecting and reproducing said recorded waves at low speed in a form substantially like the originally produced electric code impulses.

6. The method of accelerating the sending of code impulses from a telegraphic code signal transmitter to a code signal receiver, which comprises accumulating the code impulses upon storing means adapted to record acoustic impulses, reproducing the accumulated impulses as sound waves in the air, transmitting said reproduced impulses telephonically, accumulating the transmitted impulses upon storing means adapted to record acoustic impulses, and reproducing the accumulated impulses in a form adapted to operate said code signal receiver.

'1. The method of accelerating the sending of code impulses from a telepraphic code signal transmitter to a code signal receiver, which comprises producing code impulses with a signal transmitter, accumulating said code impulses at low speed upon storing means adapted to record acoustic impulses, reproducing the accumulated impulses at high speed as sound waves in the air, transmitting said reproduced impulses telephonically, accumulating the impulses at high speed upon storing means similar to the rst-mentioned storing means, reproducing the accumulated impulses at low speed, and operating a signal re'- ceiver with said reproduced code impulses.

8. Telegraphic apparatus comprising a telephonic transmission system, at the sending end thereof a slow speed sending signal recorder, means for driving the recorder at low speed, means for storing impulse signals in the recorder while moving atlow speed, means-for subsequently driving the recorder at high speed, means responsive to said recorder while moving at high speed for producing aerial sound wave signals corresponding to said impulse signals, for transmission through said system, and, at the receiving end of said telephonic system, a receiving signal recorder, means for driving the recorder at high speed, means responsive to the aerial sound wave signals produced by lsaid telephonic system, for storing impulse signals in the receiving recorder while moving at high speed,

means` for. subsequently driving the receiving recorder at low speed, and means responsive to the receiving recorder while moving at low speed, for reproducing the impulse signals.

VANNEVAR BUSH. 

